Hydraulic tailstock



March 12, 1929. s, w H

HYDRAULIC TAILSTOCK Filed April 1927 Patented Mar. 12, 1929.

UNITED STATES PATENT OFFICE.

STANLEY W. BATH, F WORCESTER, MASSACHUSETTS, ASSIGNOR, BY MESNE ASSIGE- MENTS, T0 JOHN BATH, 0F WORCESTER, MASSACHUSETTS.

HYDRAULIC TAILSTOCK.

Application filed April 7,

This invention relates to means for operating the tail center of a grinding machine or other similar machine tool. In such machines, articularly when used for duplicate worli, it is very important to reduce the timeand eflortof changing the work to the lowest limit, so that (production may be correspondingly increase It is the general object'of my invention to provide operating means of the hydraulic type, and more specifically to provide hydraulic mechanism which may be entirely controlled by a single valve.

With this eneral object in View, I preferably provide a construction in which a restricted exhaust passage is utilized, and I also preferably provide a spring for moving the tail center in one direction, the center being moved in the opposite direction by hydraullc pressure.

In the preferred form shown in the drawing, the center is advanced toward the work by spring pressure and is withdrawn bydraulically, but this arrangement is not always essential and may be reversed if desired.

My invention further relates to arrangements and combinations of parts which will be hereinafter described and more particu- 3o larly pointed out in the appended claims.

A preferred form of the invention is shown in the drawings in which Fig. 1 is a sectional front elevation of a tail stock embodying my improvements;

Fig. 2 is a'partial plan view of certain parts;

Fig. 3 is a detail sectional view, taken along the line 3-3 in Fig. 1; and

F i 4 is a sectional elevation, taken along the line 4-4 in Fi 1.

Referrin to the rawings, I have shown portions 0 a grinding machine in which the work W is supported on a head center 10 and a tail center 11. The work is shown as being in the form of a tap blank and is rotated by a dog. or driver 12.

A grinding wheel G is mounted for relative movement axially of the work, and the tail center 11 is cut away on the back side, as shown in Fig. 2, so that the wheel may be entirel withdrawn from the work after the grinding operation is completed. The tail center 11 is mounted in a sleeve or support 13, slidable in a bearing portion 14 of 1927. Serial No. 181,875.

rear end of the bearing portion 14 by bolts '21. Access to'the bolts '21 is obtained by cutting away the sides of the frame 20, as indicated at 22 in Fig. 4. I v

A piston rod 25 is axially mounted in the sleeve 13 and is secured therein by a cross pin 26. The rod 25 extends through an intermediatebearing 27 and a stuifing box 28, both mounted in the frame 20. A piston is fixed to the rear end of the rod 25, said piston comprising a washer 29, 'a' yielding packing 30, and a iston head 31, said parts being secured to t e end of the piston rod by a clamping nut'32. The iston ismovable axially in a chamber 33 in the'frame' 20, said chamber being provided with an inlet passage 34 connected y a pipe 35 and T 36 to a supply pipe 37 and an exhaust pipe 38. 'A quick-opening gate valve 39 is provided in the supply pipe 37, the valve being opened and closed manually by a handle 40. Oil or other fluid under pressure is supplied through a flexible connection 41 to the valve 39. The details of construction of the valve 39 are clearly shown in Fig. 3.

The exhaust pipe 38 is preferably eon nected to a pipe 43 of reduced section, having an exhaust valve 44 mounted thereon and connected to a flexible drain pipe 45. The outer wall of the piston chamber or cylinder 33 is formed by a'cap 47 bolted to the end of the frame 20 and having a recessed hub or projection 48 which receives a coil spring 50 which is seated between the piston head 31 and a washer or plate 51 engaged by an adjusting screw 52. The spring 50 is adapted to press the tail center 11 yieldingly toward the work, and the pressure of the spring may be varied and adjusted as desired by means of the screw 52.

Having described the construction. of my improved tail stock and its operating mechanism I will now describe the method of using the same. In normal operation, the exhaust Thework thus released drops automatical-f' an or receiver andthe tive position, atthe same time forcing the.

opening in the valve 44.

valve 44 is opened an amount suflicicnt to 1y into a suitable operator immediate yreplacesthe finlshed article with a newpiece of ,work to be ground. He thencloses the valve 39, and the spring 50 returns the tail center 11- to operaexcess oil out of the cylinderjhrough the exhaust p'pe 38 and through the restricted The operator is thus able. to withdraw and thereafter advance the tail center by merely". opening and closin thexquick acting valve)- 39, an operation w ich can be very easily? performed; Moreover, the tailvcenter 11 is;

i always forced'against the work with a definite and predetermined-spring pressure.v As

the oil is taken from and'returned to the supply tank of the machine, an abundant supply of'oil is always available, and no perceptible loss is incurred in this method of operation, even if the valve 44 does remain partially open whilethe pressure is being applied to the pistonto withdraw the tail center.

This construction avoids the use ofthree: valves or other com heated mechanism le and convenientv wa and is found veryj-relia inoer'ation. 7

aving thus described my invention and the advantages thereof I do not wish to be limited to the details herein disclosed other-- y withdraw the tail center restricted ex wise than as set forth in the claims, but what I claim is I 1. In amachi'ne tool, a tail stock, a tail center slidably mounted therein, a s ring eifective to move said tail fcenterin one irection, acylinderand, piston associated with said tail center to move the same in the op posite direction, means to supply oil under pressure to said cylinder, a valve controlling said fluid supply,- and?a'tTcontinuously open aust assage for'said cylinder throughwhich sai cylinder, is drained when said controlvalve is-el o'sed; 1 1

2. In .afmachirie' tool, a"tail=' stock, a tail-f center slidably mountedi therein, a spring effective to move said tailcenter in one direc-. tion, a cylinder and piston associated with said" tail center to move thesame inthe opposite direction "means-V tosupply oil under pressure tosaid' cyI inder,-a valve controlling said fluid supplyiuan exhaust connection for said-cylinder1w 'ch is continuously open ".during. normal. operation," and means to ad- 3..In a machine tool, a tail stock, a tail center slidably mounted'thereim'a s ring effective to move said tail center in one irection, a cylinder and piston associatedwith said tail center to'move the same in the opposite direction, means to supply oil under pressure to said cylinder, at quick-acting valve controlling said fluid supply, an 'exustably restrict the opening in said exhaust connection.

haust connection for said cylinder which is; continuously open during normal operation t and a manually adjustable valve in sai exhaust connection by which the rate of return movement of said center to operative position may be varied and controlled.

In testimony whereof aiiixed my signature.

v STANLEYW. BATH,

I have hereunto" 

